1. Field of Invention
The present invention relates to an apparatus and a method for driving the light source of a projector, and particularly to an apparatus and a method for driving the light source of a projector capable of avoiding flicker.
2. Description of the Related Art
Currently, a projector is equipped with a mercury lamp as the light source thereof. FIG. 1 is a schematic block diagram showing a conventional apparatus for driving a mercury lamp. The driving apparatus includes a lamp driver 101 and a mercury lamp 102. The driving mode of the mercury lamp 102 can be seen in FIG. 2. The lamp driver 101 receives an input voltage 111 and an enabling signal 112, then produces an alternative driving signal 113 for driving the mercury lamp 102. If the frequency of the driving signal 113 does not match the frame rate of a projector, or there is no phase-synchronization between them but with matched frequencies, a flicker displaying occurs.
A frequency match means the frequency of a driving signal 113 is the same as the frame rate, or the frame rate is an integer multiple of the frequency of a driving signal 113. A phase-synchronization means every pulse of a driving signal 113 locates always between two adjacent frame fields. FIG. 3 shows that the frequency of a driving signal 113 matches the frame rate, but with a phase discord, wherein 301-305 are five consecutive frame fields.